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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.internal.widget;
     18 
     19 public class ScrollBarUtils {
     20 
     21     public static int getThumbLength(int size, int thickness, int extent, int range) {
     22         // Avoid the tiny thumb.
     23         final int minLength = thickness * 2;
     24         int length = Math.round((float) size * extent / range);
     25         if (length < minLength) {
     26             length = minLength;
     27         }
     28         return length;
     29     }
     30 
     31     public static int getThumbOffset(int size, int thumbLength, int extent, int range, int offset) {
     32         // Avoid the too-big thumb.
     33         int thumbOffset = Math.round((float) (size - thumbLength) * offset / (range - extent));
     34         if (thumbOffset > size - thumbLength) {
     35             thumbOffset = size - thumbLength;
     36         }
     37         return thumbOffset;
     38     }
     39 }
     40